/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.runners.gaia.translation.wrappers.streaming;



import com.bff.gaia.unified.runners.core.KeyedWorkItem;

import com.bff.gaia.unified.sdk.coders.Coder;

import com.bff.gaia.unified.sdk.util.WindowedValue;

import com.bff.gaia.api.common.typeinfo.TypeInformation;

import com.bff.gaia.api.java.functions.KeySelector;

import com.bff.gaia.api.java.typeutils.GenericTypeInfo;

import com.bff.gaia.api.java.typeutils.ResultTypeQueryable;



import java.nio.ByteBuffer;



/**

 * {@link KeySelector} that retrieves a key from a {@link KeyedWorkItem}. This will return the key

 * as encoded by the provided {@link Coder} in a {@link ByteBuffer}. This ensures that all key

 * comparisons/hashing happen on the encoded form.

 */

public class WorkItemKeySelector<K, V>

    implements KeySelector<WindowedValue<SingletonKeyedWorkItem<K, V>>, ByteBuffer>,

        ResultTypeQueryable<ByteBuffer> {



  private final Coder<K> keyCoder;



  public WorkItemKeySelector(Coder<K> keyCoder) {

    this.keyCoder = keyCoder;

  }



  @Override

  public ByteBuffer getKey(WindowedValue<SingletonKeyedWorkItem<K, V>> value) throws Exception {

    K key = value.getValue().key();

    return GaiaKeyUtils.encodeKey(key, keyCoder);

  }



  @Override

  public TypeInformation<ByteBuffer> getProducedType() {

    return new GenericTypeInfo<>(ByteBuffer.class);

  }

}